Enhanced low field magnetoresistance at room temperature in La0.7Sr0.3MnO3/SrTiO3(SrZrO3) composites

Enhanced room temperature magnetoresistance (1.5–2.5% at H=100 Oe) is observed for composites La0.7Sr0.3MnO3/SrMeO3 (Me=Ti, Zr) with compositions close to the percolation boundary. Firing of the mechanical mixture of La0.7Sr0.3MnO3 (LSM) and SrMeO3 at T=900–1200°C results in significant interaction between constituents and in the shift of the percolation threshold to higher LSM content. The values of enhanced magnetoresistance, observed near percolation boundaries, are poorly dependent on firing temperatures but differ significantly for different insulating components.